This invention relates to the use of keyboards as in typewriter, computer, musical instrument, and other keyboard devices where the hands manually operate the keyboards. Traditionally, experienced, trained typists hold their hands aloft from a keyboard in use so that their wrists are in a neutral or unextended position, or slightly flexed. The same kind of position is useful for pianists and others who do a lot of keyboard work either with musical instruments, computers, typewriters and the like.
The widespread use of computers has brought the keyboard to a large number of people who have never been adequately trained in proper hand posture. Most untrained people tend to let their wrists droop, i.e., go into extension and often have the wrist rest directly on a work surface immediately in front of the keyboard. This posture of wrist extension puts excessive pressure on the median nerve in the carpal tunnel and can lean to debilitating carpal tunnel syndrome disease. This disease is a major cause of lost time and wages in the work place in the United States.
It is known that one can reduce the incidence of carpal tunnel syndrome by forcing the wrist into a neutral, i.e., not hyper-extended or hyper-flexed position. This can be accomplished by wearing a splint. Splints force the hand to maintain a certain prescribed rest position and tend to limit its motion from that rest position.
In another method of attempting to reduce the problem, the wrist can be supported in such a way that it cannot go into extreme hyper-extension. Retrofit extensions of keyboards of computers have been available made out of hard plastic material or in other firm constructions. Such baseboard extensions often start at the level of the base of the keys and continue downward to a supporting table surface. Often, such modifications in keyboards do have the effect of offering some wrist support, but generally, they are not high enough from the operating surface over which the wrist moves to be a truly effective device. If they were made higher, they could further limit wrist hyper-extension but might well interfere with access to certain keys, particularly keys in the lower row where the keyboard is at an angle. Hard supports such as hard plastics or other firm and undistorting supports have the undesirable effect of putting excessive pressure on a very small wrist area. High pressures can lead to undesirable side effects and, in fact, can aggravate the symptoms of carpal tunnel syndrome. Foam rests of a single layer have been used. Such foams are usually made of firm material and, as such, do not cradle the wrist.